Guided wave structural health monitoring using inductively coupled embedded sensors

Conventional SHM systems typically rely on permanently attached sensor networks glued on to a structure. These add complexity and weight through either a wiring requirement or the use of wireless sensing nodes. This paper reports on an alternative approach whereby the wire between transducer and ultrasonic equipment is replaced by an inductive coupling. This allows a passive small sensor unit to be embedded into a composite component. Here a model is presented to describe the performance and optimization of such a coupling. The resulting sensors are embedded in a CFRP component and shown to exhibit excellent performance. Signal processing to account for the effects of misalignment is described. Finally, the ability of such a system to detect typical impact damage is demonstrated.